Lightning characteristics based on data from the Austrian lightning locating system

Abstract

We compare various lightning characteristics measured by the Austrian lightning locating system [Austrian Lightning Detection and Information System (ALDIS)] with those found in the literature. The latter are typically based on measurements of lightning electric fields. We show that lightning peak electric fields due to subsequent strokes measured by the ALDIS are similar to those in the literature. However, the ALDIS data do not show the usual ratio of about 2:1 between the median values of the field peaks for first and subsequent strokes. Although the flash detection efficiency of the ALDIS system in the area of investigation is estimated to be higher than 90%, one of the best for such systems all over the world, the observed percentage of single-stroke flashes and the average number of strokes per flash seem to suggest that the stroke detection efficiency is appreciably less than 90%. The ALDIS data indicate that larger strokes are preceded by longer interstroke intervals. The mean flash duration of 175 ms measured by ALDIS is similar to the typical flash duration found in the literature. Strokes with larger field peaks tend to have higher average field rates of rise. Since many lightning parameters show a large scatter for different thunderstorm days, long-term data from lightning locating systems are more representative of average lightning compared to data derived from electric field measurements typically performed during a few thunderstorms.